James Pan

原题网址：https://leetcode.com/problems/excel-sheet-column-title/ Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 1 -> A 2 -> B

原题网址：https://leetcode.com/problems/integer-to-roman/ Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 方法：理解罗马数字的规律。二分法。 public clas

原题网址：https://leetcode.com/problems/roman-to-integer/ Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 方法：理解罗马数字。 public class Solut